Bean Leaf Beetle is Active
Posted: May 29, 2012
Identifying the pest is the first step to management. The key characteristic to identify the adult beetle is a small black triangle immediately behind the head of the beetle. The feeding damage was characteristic small, round holes in the leaves of the young plants. Adult beetles will also chew round holes into the pods of beans later in the season.
Bean leaf beetles overwinter as adults in grassy fields, wooded and weed y areas. The adults must have survived well in the hay fields surrounding this new vegetable production area, and then happily moved into the new bean crop. This insect will complete two generations per year in our area. The larvae feed on the roots of bean plants, but this feeding is not believed to cause major damage.
Here is a link to a good fact sheet about this pest: http://pubs.ext.vt.edu/444/444-009/444-009.html